How to measure the real lenght of a curve on solidworks?

Thank You David Thomas! I thought it would be better to add a tutorial. And i can do it now. Thanks again!
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Step 1:
If you have a sketch like that and you want to measure it, so start with the next step.
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Step 2:
Click on the arrow on the top, then Tools, then Measure... (You should be editing your sketch)
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Step 3:
You will see a ruler that you can move with your mouse. Click on the curve when measure tool is selected.
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Step 4:
You will see the Arc Lenght and Chord Lenght in a box.
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Step 5:
You can use that tool for both 2d and 3d sketches.